This article draws from Morningstar Direct data on December 2018 and full-year 2018 open-end mutual fund and ETF flows (excluding money-market funds and funds of funds), and focuses specifically on the 78 firms (four fewer than in November) with between $10 billion and $100 billion each in mutual fund and ETF AUM. Nine of those firms gained net inflows in December, and 25 gained net inflows for 2018.

Edward Jones'Bridge Builder brought in an estimated $15.838 billion in net inflows in 2018, more than any other midsize fund firm and up from $13.786 billion in 2017 (when it also led the pack for the year). Other big 2018 inflows winners included: First Trust, $9.935 billion (up from $9.726 billion); Morgan Stanley, $6.753 billion (up from $4.187 billion); Goldman Sachs, $6.47 billion (up from $107 million); and Baird, $4.337 billion (down from $8.752 billion).

Yet the picture looked a big different in December. Direxion brought in an estimated $271 million in net inflows in December, up from $18 million in net outflows in November. Other big December inflows winners included: Alps, $187 million (up from $167 million in net outflows); Van Eck, $145 million (up from $68 million in net outflows); Great-West, $100 million (up from $8 million); and Morgan Stanley, $68 million (down from $882 million).

On the flip side, 2018 was another rough year for Harbor, which suffered an estimated $21.238 billion in net outflows, more than than any other midsize firm and up from $13.451 billion in 2017 (when it also led the pack). Other big 2018 outflows sufferers included: TCW, $14.454 billion (up from $1.265 billion); Wells Fargo, $11.845 billion (up from $9.607 billion); American Century, $11.718 billion (up from $6.593 billion); and First Eagle, $10.889 billion (down from $1.278 billion in net inflows).

Like on the inflows side, the December outflows picture was a bit different from the full year. Harris' Oakmark led the midsize pack with an estimated $5.007 billion in net December outflows, up from $2.607 billion in November. Other big December outflows sufferers included: AQR, $3.137 billon (up from $1.516 billion); First Eagle, $2.517 billion (up from $1.214 billion); BNY Mellon (including Dreyfus), $2.223 billion (up from $1.371 billion); and Harbor, $2.185 billion (up from $1.737 billion).

As a group, the 78 midsize fund firms suffered an estimated $61.894 billion in combined net outflows in December, equivalent to 2.09 percent of their combined AUM. That's up from $29.886 billion in November.

For all of 2018, those same midsize fund firms suffered an estimated $140.709 billion in combined net outflows, equivalent to 4.75 percent of their combined AUM. That's up from $6.944 billion in net outflows in 2017.

Across the entire industry, long-term mutual funds and ETFs brought in a combined $162.401 billion in net inflows last year, equivalent to 0.96 percent of their combined AUM. That's despite $82.641 billion in combined net outflows in December alone, equivalent to 0.49 percent of the industry's combined AUM. Passive funds brought in $59.739 billion in net inflows in December, while active funds suffered $142.26 billion in net outflows.